The article discusses the chemical characteristics of sewage sludge. The researchers analyzed the composition of sewage sludge to understand its properties. They found that sewage sludge contains various chemicals, including nitrogen, phosphorus, and potassium, which are important for plant growth. Additionally, the researchers identified the presence of organic matter in sewage sludge, which can be beneficial for soil health. Overall, the study provides insights into the chemical makeup of sewage sludge and its potential uses in agriculture.